1. Field of the Invention
The present invention relates to an air-conditioning system for integrating multiple areas, and more particularly to a multi-airconditioning system for including a plurality of multi-airconditioner groups each composed of one or more indoor units shared with a single outdoor unit, resulting in wide-area air-conditioning effect.
Individual multi-airconditioners can be freely grouped into several multi-airconditioner groups. Individual multi-airconditioner groups are connected in parallel to a CPU (Central Processing Unit), such that a time consumed for controlling predetermined multi-airconditioning groups can be reduced. The remaining multi-airconditioner groups can be normally controlled even though one multi-airconditioner group encounters unexpected errors, resulting in increased control reliability of an overall system.
2. Description of the Related Art
FIG. 1 is a block diagram illustrating a conventional multi-airconditioning system (also called a multi-airconditioner).
Referring to FIG. 1, the multi-airconditioner 30 includes a single outdoor unit 20 and a plurality of indoor units 10 shared with the outdoor unit 20. Individual indoor units 10 are installed for every room, or are installed at intervals of a predetermined distance.
The multi-airconditioner includes individual indoor units shared with a single outdoor unit, such that it has higher operation efficiency as compared to a conventional single-type airconditioner in which an indoor unit is connected to an outdoor unit on a one to one basis, resulting in reduction of both power consumption and installation space for the outdoor unit.
The multi-airconditioning system can enter a control command in all the indoor units to be cooled simultaneously, or can also enter the other control command in some indoor units to be cooled, resulting in greater convenience for a user. Typically, the aforementioned multi-airconditioner installs one outdoor unit on each floor in a building, and installs an indoor unit shared with the outdoor unit for each room contained in the floor.
Therefore, a multi-floor building includes a multi-airconditioner 30 comprised of a single outdoor unit 20 and a plurality of indoor units 10 on each floor of a building.
The outdoor unit 20 must control or manage individual states of its associated indoor units to implement a simultaneous cooling function or a partial cooling function. Therefore, if a user enters a desired cooling command in a specific indoor unit 10, the outdoor unit 20 connected to the indoor unit 10 recognizes which one of the indoor units has received the cooling command, such that it adjusts the degree of condensation of a refrigerant, resulting in effective air-conditioning implementation.
However, if unexpected errors occur in the indoor units 10 for use in the multi-airconditioner, an administrator or manager must access the outdoor unit 20 connected to the plurality of indoor units 10 as shown in FIG. 1, and must enter control commands for repairing/managing the erroneous indoor units in the outdoor unit 20. If outdoor units are installed for every floor as in a huge building, the multi-airconditioner requires a long period of time and expensive costs to manage the outdoor unit.
Therefore, there has recently been developed a CPU (Central Processing Unit) 40 connected to the multi-airconditioners 30 installed on every floor, such that the administrator or manager can centrally control a plurality of outdoor units and their associated indoor units without accessing individual outdoor units by means of the CPU 40.
However, the conventional CPU 40 is connected in series to individual multi-airconditioners, such that an unexpected time delay occurs in a signal transmission time of the CPU 40 if the number of either outdoor units or indoor units contained in the multi-airconditioner increases.
If there is an error in only one outdoor unit from among many outdoor units 20 connected to the CPU 40, all the indoor units 10 connected to a corresponding outdoor unit cannot be controlled, and the remaining outdoor units and their associated indoor units also cannot be controlled, resulting in greater inconvenience of a user.
Furthermore, the sequential flow of signals is made unavailable even when an unexpected error occurs in a communication network connecting the CPU 40 with a plurality of multi-airconditioners, such that the CPU 40 is unable to control the multi-airconditioners.